I know it's an often topic but haven't found any solution for my problem.
I`m working on a book with lamp photos - I was adjusting photos in Photoshop in sRGB mode. For instance, I have the lamp on a grey wall - in Photoshop I've made the wall colorless (with saturation set to 0%) and the lamp remains in color.
After that, I made a document in InDesign using such adjusted photos in sRGB color profile. Later I've exported a PDF file for print with color conversion set to preserve numbers and with the destination set to Coated Forga27 (a requirement set by the printer).
I've printed a proof with some photos and the grey wall appears a bit green-ish. So - finally - my question is: is there a successful way to convert to CMYK in which the grey remains grey? My suspicion is that the grey values from Photoshop are later translated into all CMYK values, not only a K value.
P.S. I found this post: How do I convert an RGB black and white photograph to just CMYK black
but that method used on my projects just deletes hue and saturation layers and changes the color of my whole project.